(1) Field of the Invention
This invention relates to a method of producing a carbonated beverage and a unitary carbonated beverage package suitable for performing the method of the invention.
Carbonated non-alcoholic beverages are generally packaged and distributed in glass bottles or metal cans. About 85 to 90% of the contents thereof constitutes water. Thus, a large percentage of the cost of handling and distribution of such beverages is essentially expended on handling and distributing water. The use of glass bottles as the packaging medium has the additional disadvantage that, for economic use, the bottles should be returnable. Naturally, the cost of transporting empty bottles and sterilizing them prior to refilling adds to the final cost of the beverage.
An attempt to lower the cost to the consumer of fruit flavoured non-alcoholic beverages has been made by the marketing of fruit syrups which are diluted with water by the consumer prior to consumption. The resulting beverage is not, of course, carbonated and does not have the characteristic pungent taste or "bite" and sparkle of a carbonated beverage. Similarly, dry fruit flavoured powders are widely available, which when dissolved in water in the proper ratio yield a fruit flavoured beverage. Naturally, such beverages also do not have the characteristic bite and sparkle of carbonated beverages and, furthermore, many popular flavours such as the ginger and cola flavours can not conveniently be transformed into dry powder form.
(2) Discussion of the Prior Art
In an attempt to advance the non-alcoholic beverage industry, Canadian Pat. No. 723,604 (Larsen, et al) discloses a method for packaging and distributing carbonated non-alcoholic beverages which avoids the need for handling large amounts of water and also obviates the need for returnable glass bottles. Larsen et al packaged a fruit syrup of suitable concentration in a valved pressure container (aerosol container), together with a non-toxic pressure-generating propellant such as carbon dioxide or a mixture of carbon dioxide and another non-toxic propellant. A carbonated beverage may then be produced by a consumer by dispensing a suitable amount of the carbonated syrup into a glass of water. However, this method suffers from various disadvantages, including the need for a given consumer to purchase an expensive valved pressure container and the possible need to use various propellants other than carbon dioxide such as, nitrous oxide, nitrogen or fluorinated hydrocarbon. Furthermore, release of the carbonated syrup into a glass of water results in a major discharge of carbonation, which effect is enhanced if, as often will be the case, the glass of water contains ice cubes. In consequence, the method outlined in Canadian Pat. No. 723,604 is inadequate to consistently produce in the home carbonated beverages possessing an adequate degree of carbonation, along with the characteristic desired pungent taste or bite and sparkle.
A further attempt to solve the problem of affording home production of carbonated beverages of good quality in small or large quantities is described in Canadian Pat. No. 1,052,618 (Kennedy). In this prior disclosure, a dry beverage mix contains phosphoric acid in a dry, stable form. The beverage mixes described rapidly dissolve in water, which may be carbonated. The particular compositions disclosed seek to duplicate the unique cola or other soft drink flavour of commercial offerings, which is partly due to interaction between the phosphoric acid and other flavour components during an aging period of the liquid flavour base. The prior patent seeks to achieve this object by including in the flavour base an amount of mono alkali ortho phosphate at least equimolar to the phosphoric acid content of the flavour base. A variety of carbonation systems is disclosed for providing suitably carbonated, flavourful beverages. Included among these are addition of the dry beverage particles to pre-carbonated water or combination of the dry beverage particles with a carbonation system which is then added to tap water. Examples of suitable sources of pre-carbonated water are the use of bottled pre-carbonated water, commonly known as "club soda" or the use of pressure carbonators which utilize carbon-dioxide charged cylinders to carbonate water as it is dispensed. A further possibility is the use of carbon-dioxide-loaded zeolite molecular sieves. This prior process tends to suffer from disadvantages of insufficient carbonation and difficulty in dissolving the crystals or the expense and inconvenience of providing a point-of-consumption carbonation system or the use of molecular sieves, which when spent remain as residues in the bottom of the glass or receptacle being employed.
Canadian Pat. No. 1,103,982 (McCarty et al) discloses a carbonated beverage mix comprising a fructose sweetener, a flavourant, an acidulant and an instant carbonation device effective to carbonate the beverage when the mix is brought into contact with a beverage-making liquid, for example water. The preferred instant carbonation device is a carbon dioxide-loaded molecular sieve device and the method disclosed for making such beverages suffers from similar disadvantages to those discussed above with respect to the Kennedy Canadian Pat. No. 1,052,618.
Also of interest is Canadian Pat. No. 1,173,289 (Coeffier) which relates to a process for the manufacture of a carbonated beverage comprising preparing a solution of sugar and water and adding thereto a second solution containing fermentation agents to promote the formation of carbon dioxide by fermentation so as to effect carbonization of the beverage. The fermentation is terminated before the occurrence of significant alcohol formation and such termination is taught as being achieved by abrupt cooling. Treatment is then carried out to avoid further fermentation when the beverage returns to ambient temperature, for example pasteurization. Thus, Coeffier describes an industrial process similar to beer production employing pasteurization and also filtration techniques requiring expensive equipment not available to the domestic consumer.
Finally, Canadian Pat. No. 1,124,569 (Saleeb et al) relates to a process for preparing carbonated liquids with coated crystalline zeolites or coated charcoal. Thus, a process of carbonating an aqueous liquid is disclosed which comprises contacting an aqueous liquid under atmospheric or super atmospheric pressure with an effective amount of an adsorbent coated with a layer of a monomeric organic compound with a molecular weight below 500 and having adsorbed therein at least 20 cubic centimeters of carbon dioxide per gram of adsorbents, said adsorbent being a crystalline zeolite or an activated charcoal. This prior proposal also suffers from similar disadvantages to those discussed above, in that it fails fully to address the problem of achieving desirable bite in the eventual beverage and the fact of needing to employ expensive adjuncts as a source of carbon dioxide, namely the crystalline zeolite or activated charcoal. The problem also remains of the disposal of the spent zeolite or charcoal.
Attempts to commercialize home preparation of carbonated beverages have not achieved lasting success over the years. The principal shortcoming of the several techniques available has been that the consumer-prepared carbonated beverage has been significantly inferior in one or more aspects to the commercially available bottled or canned carbonated beverages. Generally speaking, quantity and quality of carbonation in home-produced beverages has been inadequate and bubble size and duration of effervescence compare unfavourably with commercially-available beverages.
On the other hand, significant advantages obtain with respect to home preparation of carbonated beverages. Thus, the use of glass, metal or other bulky containers can be avoided, the necessity of bottling, shipping and storing carbonated beverages consisting mostly of water is eliminated and portability is greatly enhanced. Furthermore, the problem of disposable and returnable cans and bottles would be alleviated.
U.S. Pat. No. 2,073,273 (Wetstein) discloses preparation of a carbonated beverage wherein water, sweetener and flavour are placed in a small pressure vessel and a metal cartridge containing carbon dioxide is inserted into the sealed vessel. Movement of the cartridge causes piercing thereof, thereby injecting carbon dioxide into the water to form the carbonated beverage. The carbon dioxide also pressurizes the vapor space above the liquid, thereby enabling the carbonated beverage to egress the vessel through a serving nozzle when an external valve is opened. This device met with some measure of success in preparing unflavoured and unsweetened carbonated water for home use but the carbonation was not equivalent to that of bottled club soda, nor was there any financial advantage since the cartridges were costly.
The prior art includes a significant number of dry compositions for use in preparing carbonated beverages at home. In most cases, a source of carbonate and acid is combined with sweeteners and a source of flavour so that upon addition of the composition to a glass of water, the carbonate and acid react to yield carbon dioxide and at least some measure of carbonation to the beverage. Among the prior patents describing this and similar techniques, are U.S. Pat. No. 2,603,569 (Alther) which discloses the carbonation of a citric acid-sucrose complex with a sodium bicarbonate-sucrose complex; U.S. Pat. No. 2,742,363 (Hughes) which claims a combination of an alkali metal bicarbonate and sulfonic acid ion exchange resin in its hydrogen form, U.S. Pat. Nos. 2,851,359 and 2,953,459 (Diller) in which a highly soluble phosphate and slowly soluble phosphate are combined with an alkali metal or ammonium carbonate or bicarbonate to prolong ebullition of the beverage. U.S. Pat. No. 3,241,977 (Mitchell et al) which discloses chemical carbonation with citric, adipic or tartaric acid in finely divided form and which is said to approximate the carbonation sensation of cola-type beverages, U.S. Pat. No. 3,441,417 (Feldman et al) which discloses a dry beverage composition adapted to be reconstituted with water to form an effervescent beverage and which includes as an essential carbonating ingredient an organic compound having a carbonic acid anhydride group capable of controlled hydrolysis in water to release carbon dioxide at a substantially uniform rate, and U.S. Pat. No. 3,667,962 (Fritzberg et al) which describes a carbonation composition utilizing two distinct bodies formed from an aqueous solution of a saccharide, one containing an edible food acid and the other an edible bicarbonate. Upon addition to water, the two tablets dissolve quickly and react to evolve carbon dioxide. This system has not been perfected nor approved by the F.D.A.
Many of the dry powder chemical systems have a common and acknowledged defect, namely an unpleasant taste in the beverage directly resulting from the components of the powder. Various techniques have been disclosed in the above-mentioned patents to attempt to mitigate this disadvantage, but such techniques are either complicated or expensive or not entirely successful.
Attention is also directed to U.S. Pat. Nos. 2,631,521 (Atkins, Jr.), 2,694,641 (Atwood, et al), 2,712,998 (Vosseler), 3,112,201 (Saez), 4,009,285 (Spooner) and 4,423,670 (Tenison).
In summary, none of the above-discussed prior proposals produces adequate and controlled carbon dioxide production under pressure, nor have they met with F.D.A. approval due to their instability.